Electropneumatic brake equipment



Jan. 19, 1937. D. L, 'MONEAL I 2,068,345

ELECTROPNEUMATIG BRAKE EQUIPMENT Filed Oct. 19, 1955 2 Sheets-Sheet l ATTORNEY' Jan. 19', 1937. D, L, MCNEAL f 2,068,345

ELECTROPNEUMAT I C BRAKE EQUIPMENT FigA INVENTOR nnNALn L. MnNEAl'.

ATTORNEY Patented Jan. 19, 1937 UNITED STATES PATENT CFFICE ELECTROPNEUMATIC BRAKE EQUIPMENT Application October 19, 1935, Serial No. 45,698

22 Claims.

This invention relates to brake equipment and more particularly to brake equipment for high speed railway trains and traction vehicles.

Modern conditions require that railway trains and traction vehicles be operated at relatively high speeds. When such trains and vehicles are operated at high speed a braking equipment must be provided which combines a high degree cf reliability with flexibility so that the train or Vehicle can be handled with the utmost regard for safety. This invention relates to train braking systems adapted for use on high speed trains such for example as equipment of the general character disclosed and claimed in the copending application of Ellis E. Hewitt, for Brake equipment, Serial No. 741,063, led August 22, 1934, and assigned to the same assignee as thisl application.

In the braking equipment disclosed in the copending application above referred to a master relay device is employed having an electric relay portion and a pneumatic relay valve portion. The electric relay portion is controlled by the differential pressures between the control pipe and the straight air pipe, acting on opposite sides of a diaphragm for actuating switch contact members which control circuits for energizing an application magnet valve device, and a release magnet valve device, to control the application and release of the brakes. The pneumatic relay valve portion parallels pneumatically the functions of the electric relay portion and its associated application and release magnet valve devices, in case the electric circuits should fail or be interrupted intentionally by directly controlling the flow of air to and from the straight air pipe in response to the supply of uid under pressure to, or the release of fluid under pressure from, the control pipe. The relay valve prtion is so constructed that a slightly greater differential of pressure between the control pipe and the straight air pipe is required to cause its operation than is required to cause the operation of the electric relay portion.

The present invention combines the pneumatic and electric portions of the master relay device above referred to into a structure in which the pneumatic valve portion and the electric switch portion are operated from a single element subject to the diiferential pressures between the straight air pipe and the control pipe.

An object of the invention is the provision of a master relay device of the character described comprising a compact unitary relay structure for electrically controlling the application and release of the brakes in accordance with control pipe pressure and for pneumatically controlling the application and release of the brakes in case of failure of the electric circuits that normally control the brake system.

Another object of the invention is the provision of an electropneumatic relay valve device having large capacity and operative upon a low differential in pressure across the piston for controlling the supply of fluid under pressure to, and the release of uid under pressure from, the brake cylinder of the uid pressure brake equip-ment.

Other objects and advantages of the invention will appear in part from the following description ci several preferred embodiments of the invention when read together with the accompanying drawings, in which Y Fig. 1 is a diagrammatic View of a brake equipment employing one preferred embodiment of the relay valve device, shown in section.

Figs. 2, 3, and 4 are sectional views showing other preferred embodiments of the relay valve device.

Referring to the drawings and more particularly to Fig. 1 thereof, a brake system is illustrated comprising a main reservoir I through which fluid under pressure is supplied, at a reduced pressure, by the feed valve device 2 to a main reservoir pipe 3, and through check valves 4 to the auxiliary reservoirs 5 of each braking unit. A brake valve device 6 is employed for controlling the supply of fluid under pressure from the main reservoir pipe 3 through the control pipe 'I to the master relay device 3 that comprises an electrical portion and a pneumatic portion, the electrical portion controlling an application magnet Valve device 9 and a release magnet valve device I that control the supply of fluid under pressure from the auxiliary-reservoir 5 to the brake cylinder I2, and the release of iluid under pressure from the brake cylinder to the atmosphere, and a pneumatic portion for controlling the supply of fluid under pressure to the brake cylinder I2 from the main reservoir pipe 3 through the straight air pipe I3.

The master relay device 8 comprises a casing I4 in which is operatively mounted a control piston I5 slidably mounted within a cylindrical portion of the casing I4 and connected to a baille piston I6 which is of less diameter than the control piston I5 and which is adapted to be reciprocated in a tubular bushing Il secured to the casing, said pistons being integrally connectedv by a stem I8. y

The piston I6 and the bushing Il are' so formed as to provide an always open restricted communication 29 between a pressure chamber I9 within the casing I4 which is connected to the brake cylinder I2 through the straight air pipe I3, and a piston chamber 2| at the rear face of the piston I5.

The piston chamber 22 at the front side of the control piston I5 is connected to the control pipe 1, through which fluid under pressure is adapted to be supplied to and released from the piston chamber by operation of the brake valve device 6.

Extending inwardly from the baille piston I6 and preferably integral therewith is a piston stem 26 having a circular end portion 21 which is slidably guided within a bore 28 in the wall of the casing I4. The piston stem 26 is provided intermediate the baffle piston I6 and the guide portion 21 with a rockable lever 36 carried by a bolt or bearing pin 31.

The lever 36 is contained in the pressure chamber I9 and is provided with oppositely disposed arms 46 and 41 which are adapted to control the operation of a release valve mechanism and a supply valve mechanism respectively.

The release valve mechanism comprises la plunger 48, the pilot release valve 49 and a main release valve 59. The plunger 48 is slidably guided at one end in a bushing 5| mounted in the casing. This end of the plunger is provided with a central bore 52 which is open to the chamber I9 through a passage 53 for the purpose of preventing dashpot action when the plunger is moved. Contained in the bore is a spring 54 which operatively engages the plunger and bushing and which, as will hereinafter be more fully explained, exerts a light counterbalancing pressure on the piston assembly. The plunger, adjacent its other end, is slidably guided within a bore 55 in the casing. Intermediate the bushing 5| and the bore 55 the plunger is reduced in diameter as indicated by the reference character 59 to form spaced shoulders 51 and 58 which are adapted to be operatively engaged by oppositely disposed convex surfaces 59 and 69, respectively, on the end portion of the arm 46 of the controlling lever 36, said end portion of the lever being forced to accommodate the portion 56 of the plunger. The plunger is provided with a collar 6| which is located inwardly of the bore 55 and beyond the collar is provided a screwthreaded portion 62,

The main release valve 59 is provided with a stem 63 which is in axial alignment with the plunger 48 and is positioned within a bore 65, provided at one end with a valve seat 66 for the release valve 59. The valve stem is integrally connected to a piston 61 which is slidably mounted in the bore 65, and this piston is provided with a small port 68 which constantly connects the chamber 69 at one side of the piston to a chamber 10 at the opposite side thereof, which is constantly connected with the atmosphere through a passage 1| in the cap 14 of the casing. The main release valve 50 is provided with a valve seat 15 on which, as will hereinafter be more fully explained, the pilot release valve 49 is adapted to seat, and is provided with an axial bore 16 which extends from the valve seat 15 through the valve stem 63 to the outer face of the piston 61.

The pilot release valve 49 is in axial alignment with the plunger 48 and with the main release valve 50, and is provide-d with a circular head 11. The head portion is attached in abutting relation to the screw-threaded end portion 92 of the plunger by means of a hooded nut 19.

The pilot valve 49 is provided with a stem 8| which passes longitudinally through the bore 16 in the main release valve and which at its end is provided with a stop nut 82 and a locking nut 83 for locking the stop nut against accidental turning. The stop nut is tightened down in close engagement with the circular collar 84 which is preferably integral with the valve stem 8| and is so arranged as to insure an open communication between the piston chamber 69 and the bore 16 in the main release valve stem 63 when the collar 94 is in engagement with the underside of the piston 61.

It will be understood from the foregoing description of the release valve assembly that when the pilot release valve 49 is unseated, as shown in Fig. l, there will be an open communication from the piston chamber 69 to the pressure chamber I9 through the bore 16 in the valve stem 63.

In the manufacture of the relay valve device a plunger 48, pilot release valve 49, and the main release valve 59 are secured together as a unit preparatory to being mounted in engagement. In assembling these parts the plunger 48 and the pilot release valve 49 are first connected together by means of a nut 19, then the main release valve is mounted upon the stem 8| of the pilot release valve, and finally the stop nuts 82 and 83 are turned to the position in which they are shown in Fig. l. In turning the nut 82 down tight on the collar 84, the nut 19 is adapted to be engaged by the jaws of a wrench to prevent the plunger from being turned, the stem 8| being held from turning by the engagement of the nut with the square portion 18 of the stem.

The supply valve mechanism may comprise a valve piston which in the present embodiment of the invention consists of a piston 81 and a main supply valve 88 having an annular sleeve 89 which has a pressed t with the piston within an opening provided in the piston. The piston is slidably guided in a bore 99 in the casing I4. At the inner end of this bore a valve seat 9| is provided which surrounds a passageway 92, leading from a chamber 93 at one side of the valve piston to the pressure chamber I9, the chamber 93 being constantly in open communication with the main reservoir passage and pipe 3. The main supply valve 88 is movable into or out of seating engagement with the valve seat 9| and is therefore adapted to control communication through the passageway 92.

At the side of the valve piston 81 opposite the chamber 93, there is provided a chamber 91 which is connected to the chamber through a passage 99 of small diameter provided in a choke plug 99 having screw-threaded connection with the casing.

Contained in the chamber 91 is a pilot supply valve |99 which is adapted to move into and out of engagement with a seat |95 provided on the end of the valve sleeve 89 to control communication through a central bore I 92 in the sleeve, which bore leads from the valve seat to a narrow slot |93 provided in the face of the main supply valve 88, said slot being in constant open communication with the pressure chamber I9.

Also contained in the chamber 91 are control coil springs |94 and |95 which at all times urge the supply valve 88 and the pilot supply valve |99, respectively, toward their seats. The spring |94 is interposed between, and operatively Yengages the piston 81 and a cap nut |06 which closes an opening in the casing I4 through which the pilot supply valve and springs |04 and |05 are adapted to be inserted or removed from the casing. The spring is encircled by the spring |04 and is interposed between and operatively engages the cap nut |06 and a spring seat |01 integral with this pilot supply valve.

The pilot supply valve |00 is provided with a iluted stem |08 which is slidably guided in the supply valve. When the pilot valve is seated the stem |08 extends across the slot |03 and projects a short distance beyond the face of the main supply valve and is adapted to be operatively engaged by one end of a valve controlling plunger |09 which is axially aligned with the valve piston and pilot supply valve and which is slidably guided in a bore I I0 in the casing. The lower end of the plunger has a diameter which is greater than the width of the slot |03 so that it will operatively engage the face of the main supply valve after the pilot Supply valve has been moved a limited distance from its seat.

The other end of the plunger |09 operatively engages a convex surface I I I provided on one end of the arm 41 of the control lever 3B. The opp0 site side of the arm 41 is provided with a convex surface |I2 which is adapted to engage the convex face ||3 of a fulcrum member ||4 screwthreadedly attached within a bore I I5 in the casing structure. The fulcrum member is adjustable relative to the casing 4 to compensate for unavoidable inaccuracies in manufacture and for wear on the various parts of the apparatus.

In Fig. 1 of the drawings the relay valve device is shown more or less diagrammatically in order to simplify the construction thereof. The construction of the portion of the apparatus below the main piston I5 as illustrated in Fig. l may however correspond exactly with that illustrated and described in the copending application of Ellis E. Hewitt for fluid pressure valve device, Serial No. 740,202, led August l1, 1984, and assigned to the same assignee as this application.

The electric portion of the relay device 8 comprises a stem IIG extending upwardly from the main piston I 5 through an opening in the wall I1 which stem carries at its upper end an insulating portion II8 which may be attached to the stem II6 by a bolt IIS and carries a switch contact member I2I. An end plate I 22 provides a cover for the switch chamber |20 in which switch connecting studs |23, |24, and |25 are mounted and insulated from the plate |22 by plates |25 and |21 of insulating material and insulating tubular members |28 positioned about the studs |23, |24 and I 25. Switch contact members |29, I3|, and |32 are attached to the studs |23, |24, and |25, respectively, and extend inwardly into the switch chamber |20 in such positions that the switch member |2| may bridge the switch members |29 and I3I, or |20 and |32, depending upon the position of the piston I5 and the piston stem I I6. The stud |23 is connected by a wire |33 to one terminal of a source of supply indicated by the battery |34 one terminal of which is grounded at a point I 35. The stud |24 is connected to a release magnet valve wire |30 extending throughout the length of the train and the stud |25 is connected to an application magnet valve wire |31, extending throughout the length of the train.

The application magnet valve device 9 comprises a casing containing a chamber I4| that is in constant open communication with the brake cylinder I2 through passage and pipe I3, and an application valve chamber |42 that is in constant open communication with the supply reservoir 5, and that contains an application valve |43, having a stern |44 that is operatively connected to a magnet I 45. The application valve chamber |42 contains a spring |46 for urging the valve |43 upwardly to its seat. l

The release magnet valve device comprises a casing containing a release chamber I5I that is in constant communication with the atmosphere through an exhaust port |52, and a release valve chamber |53 that is in constant communication with the brake cylinder |2 through passage and pipe I3, and which contains a release valve |54 that is operatively connected by means of a stem |55 to a magnet |55 in the upper part of the casing. A spring |00 is provided within the release valve chamber |53 for urging the valve |54 to its seat.

In assembling the several parts of the relay valve device 0 the adjustable fulcrum member II4 is screwed into the bore ||5 a sufficient distance that it cannot interfere with the proper seating of the main and pilot supply valves 00 and |00 respectively. After the supply valves 05 and |00 are properly seated and the annular stop rib |38 of the piston I5 is in contact with the cover plate |39 of the casing |4 the adjustable fulcrum member I I 4 is turned to a position such that when the curved surface I I2 of the arm 41 is in engagement with the fulcrum member ||4 a space will be provided either between the arm 41 and the plunger |09, or between the plunger |00 and the valve stem |08. This space is for the purpose of permitting suflicient movement of the piston i5 from the position corresponding to electric lap in either directionto permit suiiicient movement of the pistons to eiect operation of the magnet valve devices prior to operation of the application and release valves in the pneumatic portion of the relay. When the desired clearance exists in the movement of the arm 41, either between the surface III and the plunger |09, or between the valve engaging end of the plunger |09 and the stem |00 of the pilot supply valve I 00 the fulcrum member is no longer rotated and is secured in its proper position by turning the locking nut |4I tightly against the wall of the casing into which the fulcrum member I I4 is screw-threaded.

When the lever 36 is being moved by the fulcrum member I|4 the piston remains in its normal position so that the lever 30 rocks in a counterclockwise direction about the bolt 31 and, as a consequence, the plunger 48 and the connected release valve parts are moved in the direction toward the piston I5 against the opposing pressure of the spring 54.

Charging the Equipment In charging the equipment, iiuid under pressure from the main reservoir I, as supplied by the feed valve 2, to the main reservoir pipe 3 at a reduced pressure flows through passage 3 into the chambers 93 and 95 of the relay valve device. Fluid under pressure ows from the chamber 05 through the restricted passage 00 in the plug 03 to the pilot supply valve chamber 91. The i-low of uid from the chamber 95 to the chamber 93 is at a faster rate then the flow of iluid to the chamber 91 by way of the restricted passage 90, but since, as will hereinafter more fully appear, the pressure of the spring |04 is suiilcient to maintain the main supply valve 80 seated against full main reservoir pipe pressure in chamber 93 the communication between the chambers 93 and I9 will not be unintentionally' established. The 75 auxiliary or supply reservoirs 5 on each brake unit are charged by the ow of uid under pressure through the check valves 4 to main reservoir pipe pressure.

With the brake valve device B in release position the piston chamber 22 of the relay valve device is vented in the usual way and the piston I5 together with the several parts associated therewith will be in the position in which they are shown in Fig. l. In this position the chamber |9, and, consequently the brake cylinder |2, are in communication with the atmosphere by way of the straight air pipe I3, the pressure chamber i9, the unseated main release valve 5|) to chamber and passage 1|.

Also with the piston chamber 22 of the relay valve device vented and the parts in the position illustrated in Fig. 1, a circuit is completed from the positive terminal of the battery |34, through wire |33, stud |23, the switch contact members |28, li and |3i, the release magnet valve wire |36, the windings of the magnets |51 of the release magnet valve devices H to ground at |59, and to the grounded terminal |35 of the battery |34, thus energizing the magnets i575 of the release magnet valve devices and forcing each release valve |52 downwardly from its seat to effeet communication from the brake cylinder l2 to the atmosphere through the exhaust port E52.

Operation When the equipment is thus charged, and it is desired to make an application of the brakes the operator will move the handle of the brake valve device E to supply fluid under pressure through the control pipe 1 to the piston chamber E" of the relay valve device to effect the building up of a pressure therein corresponding to the desired degree of application of the brakes. Fluid under pressure, thus supplied to the piston chamber 22 causes the relay control piston l5 to move i'orwardly from the position illustrated in l. It will be understood that when the piston i5 is in the position in which it is illustrated in 1 the spring 54 is slightly compressed and acts through the medium of the plunger 48, lever piston stem iii, and the fulcrum member ||4 to assist uid pressure supplied to the piston chamber 22 in moving the piston i5 forwardly. This spring also acts to cushion the piston when it is moved from its forward position to its illustrated position. It will be noted that the piston i5 is pro-vided with an annular stop rib |33 which projects outwardly from the face of the piston and which is adapted to engage the inner surface of a cover plate ||1 forming the part of the cas-- ing i4 and closing the open end of the chamber 2|.

As the connected pistons I5 and I6 are moved inwardly the piston stem 2S thereof carries the bolt 31 and the central portion of the lever 36 in the same direction and as the lever 36 is thus moved, the end of the arm 41 thereof fuicrums on the fulcrum member ||4 until, as will be hereinafter more fully described, the pilot and main release valves i9 and 53, respectively, are seatedA Since the end of the arm 41 of the lever 33 is fulcrumed as ab-ove described the arm 43 is caused to move in the same direction as the pistons |5 and l5 and the stern 25, the lever rocking slightly about the bolt 31 in a clockwise direction in response to the force of the spring 5ft. and the end of the arm 41 rocking slightly on the ful- Crum member I4. The arm 46, as it thus moves, forces the plunger 48 in the same direction as the pistn 23 is moving and first causes the pilot release valve 49 to engage its seat 15, and then, through the medium of the pilot valve, causes the main release valve 53 to be moved into en4 gagement with its seat 66. As the main release valve 53 is moved toward its seat the piston 61 which moves with the valve decreases the volume of the chamber t9 and fluid in this chamber, which would be otherwise compressed by the piston 61, is permitted to ow to the atmosphere through the passage 58 in the piston, chamber 53, and the exhaust port 1|. It will be understood that the venting of the fluid from the chamber 69 instead of permitting it to be compressed, and thereby resist the closing movement of the main release valve 5|) contributes to the sensitiveness of the relay valve device as a whole.

In this position of the pistons i5 and I1 and the stem 26 the pilot and main release valves 49 and 5I] respectively and also the pilot and main supply valves |33 and 38 respectively are all in lap position. Upon a slight further inward movement of the pistons i5 and le the fixed contact member I2! is moved from engagement with the switch contact member i3! to interrupt the above traced circuit through the release magnet valve wire |36 and the magnets 51 of the release valve devices thus deenergizing the magnets and permitting the release valves E54 to he forced upwardly to their seats by the spring l53, thus closing communication from the brake cylinder i2 to the atmosphere through the exhaust port i5?. The application valve |43 and the release valve i551 that are controlled by the electrical portion of the relay valve device 3 are now also in lap position.

Upon a further inward movement of the pistons i5 and i1 from lap position the movable contact member 52| will be brought into engagement with the switch contact member E32 thus completing 1 a circuit from the battery |34 through battery E34, through wire 33, stud |23, switch contact members |29, |2l, and i312, the stud |25 and the application magnet valve wire 31, through the windings of the magnets |45 of the application magnet valve devices 9 to ground at |59 and to the grounded terminal |35 of the battery |34, thus energizing the application magnet valve devices and forcing the application valve |43 downwardly against the bias of the spring |43 to effect the supply of fluid under pressure from the supply reservoir 5 to the brake cylinder l2 through the passages and pipe i3. Fluid under pressure also iiows from the straight air pipe I3 to the pressure chamber I9 of the relay valve device and past if the piston I6 through the groove 20 to the chamber 2| until the pressure therein builds up to a value equal to, or slightly in excess of the pressure in the piston chamber 22 and forces the piston l5 to lap position to interrupt the circuit through the switch Contact members |2i and |32, thus deenergizing the winding of the magnet |45 and permitting the application valve |43 of the magnet valve device 3 to be forced to its seat by the spring |46. It will be seen therefore that the ultimate pressure effected in the straight air pipe I3 and the brake cylinder i2, and in the chamber 2| of the brake valve device, will correspond substantially to the pressure within the piston chamber 22. The space provided between the curved surface of the arm 41 and the end of the plunger |39 permits suflicient inward movement of the lever 36 and of the pistons i5 and I6, after the supply valves 49 and 5|] have seated, to interrupt the circuit through the release magnet valve ll Il wire |36 and establish the circuit through the application magnet valve wire |31 prior to unseating the supply valves and 88.

If the electric circuits and magnet valve devices operate as described, the pressure in the chamber 2| will build up at about the same rate as the pressure builds up in the piston chamber 22, so that only a small diiierential exists between the pressures on the opposite sides of the piston I5, which will not be sufficient to force the pilot valve |00 from its seat. If the circuit controlling the magnet valve devices 9 and II fail for any reason, the application of the brakes will be effected through the pneumatic portion of the relay valve device 8. When the main release valve 50 is seated the shoulder 51 on the plunger 48 acts as a stationary fulcrum for the arm 4B of the lever 36 so that as the pistons I5 and I3 and the stem 26 continue to move downwardly the arm 41 is caused to lmove in the same direction as the piston stem is moving, the lever 36 rocking slightly about the bolt 31 and the end of the arm. IIS rocking slightly on the shoulder 51.

The arm` 41 asV it is thus moved forces the plunger |09 in the same direction as the piston stem 29 is moving and said plunger being in engagement with the fiuted stem |08 of the pilot supply valve |00 causes the valve to be unseated against the opposing pressure of the spring |25. Fluid under pressure now Vflows from the chamber 01 to the pressure chamber I9 at a faster rate than fluid is supplied thereto through the restricted passage 96 in the plug 99. This results in a reduction in the pressure of fluid in the chamber 91, and, as a consequence, the pressure acting on the piston 81 to maintain the valve 88 seated is reduced.

After the pilot valve |00 has been unseated the plunger |09 engages the face of the valve 88 on each side of the slot |03. It will here be understood that the rate of reduction in the pressure of fluid in the chamber 91 by the flow of fluid to the pressure chamber I9 is such that at the time the plunger |99 operatively engages the face of the valve 88 the pressure of the springs |04 and |05 and fluid in the chamber 91 slightly exceeds the main reservoir pipe pressure in the chamber 93 acting on that portion of the valve piston which surrounds the valve 83. In view of this only'a slight increase in the pressure of fluid in the piston chamber 22 over that required to unseat the valve |00 is necessary to cause the valve 88 to be unseated against the opposing reduced seatl This partial unloading of theA ing pressure. piston 81 contributes materially 'to the sensitiveness of the relay valve device as a whole. Fluid under pressure supplied from the main reservoir pipe to the chamber 93 now flows past the unseated supply valve 88 to the pressure chamber I9 and from this chamber through the straight air pipe I3 to the brake cylinder I2 thus eirecting an application of the brakes.

Under certain conditions the supply of fluid under pressure past the main supply valve 88 to the chamber I9 may be at such a rapid rate as to momentarily produce a pressure in the cham.- ber I0 Awhich exceeds the actuating or control pressure in the piston chamber 22. It would be undesirable to permit this high pressure to act on the rear face of the control piston I5 for the reason that it would cause the piston to move towards its lap or brake releasing position and thereby permit the supply Valve 83 to seat and to remain seated until such time as the pressure in the pressure chamber I9 is reduced by ow to the brake cylinder nally below the actuating pressure in the chamber 22, at which time the piston I5 would be caused to again move to unseat the supply valve. In order to prevent this undesirable alternate unseating and seating of the supply valve 88 and to insure a continuous increase in the pressure in the pressure chamber I9, and consequently in the brake cylinder I2, a rapid ow of fluid from said pressure chamber I9 to the chamber 2| at the rear of the piston I5 is prevented by the restricted flow of fluid past the baffle piston I6 through the restricted passageway 20. By thus restricting the ow of fluid under pressure to the chamber 2 I, the rate of increase in the pressure in this chamber is slightly slower than that of the rate of increase in pressure in the piston chamber 22 so that as long as fluid under pressure is being supplied to Athe piston chamber 22 the piston I5 will not be permitted to move outwardly to permit the supply valve 88 to seat.

If the brake valve device 6 is placed in ap'- plication position and permitted to remain there until such time as iiuid pressure in the self-lapping chamber 2I equalizes the pressure in the piston chamber 22, a full application of the brakes will be effected. If however the brake valve device 6 is moved from application position to lap position before such equalization takes place, an application of the brakes that is less than full application will result, depending upon the degree of pressure in the piston chamber 22.

When the pressure in the self-lapping chamber 2| of the relay valve device becomes substantially equal to the pressure of fluid in the piston chamber 22 the spring |04 and fluid under pressure in the chamber 91 act to seat the main supply valve 38 of the valve piston 81 after which the spring |05 acts to seat the pilot supply valve |00. The supply valves, as they are thus moved to their seat shift the plunger |09 and thereby the arm 41 of the lever 3B in the same direction. Since the arm 46 of the lever is fulcrumed on the plunger 48 this movement of the arm 41 causes the piston assembly to move forward, this is, toward the position illustrated in Fig. 1.

The seating of the supply valves 88 and |00 closes the supply of iiuid under pressure to the pressure chamber I9 so that the piston assembly comes to a stop before the arm 41 of the lever engages the fulcrum |I4 and the lever 46 still maintains the release valves 48 and 50 seated.

When the relay valve device 8 is in lap position the switch contact member |2| is out of engagement with both of the switch contact members IBI and |32 so that the magnet windings of both the application magnet valve device 9' and the release magnet valve device II are deenergized and the application valve |43 and the release valve I 54 are seated. Upon the movement of the actuating piston I5 of the relay valve device in either direction from lap position the switch contact member IZI will be brought into engagement, either with the switch contact member I3| controlling the release magnet valve device II to effect the release of uid under pressure from the brake cylinders I2, or into engagement with the switch contact member |32 controlling the application magnet valve device 9 to effect the supply of iiuid under pressure to the brake cylinder I2, just prior to the operation of the pneumatic portion of the relay valve device 8 to effect a corresponding release of fluid under pressure from the brake cylinder I2, or the supply of uid under pressure thereto through the pressure chamber i9 of the relay valve device 8.

As above explained, if the magnet valve devices operate as intended to effect an application of the brakes, the change in pressure in the pressure chamber lil and in the chamber 2| takes place with sufficient promptness that the pneumatic portion of the relay valve device is not required to operate and does not operate to apply the brakes therethrough. In the case of the release of the brakes the pneumatic portion ultimately moves to release position as illustrated in Fig. 1 upon the reduction in pressure in the pressure chamber 22 to atmospheric pressure.

If the electric circuits are interrupted in such manner that the magnet valve devices cannot operate to control the release of the brakes they will be released through operation of the pneumatic portion of the relay valve device 8. Assuming that the several parts of the relay valve device are in lap position when uid under pressure is vented from the piston chamber 22 through the brake valve device 6 to the atmosphere to effect a release of the brakes, iiuid under pressure in the self-lapping chamber 2i acting on the rear face of the piston l5 causes this piston, together with the baiiie piston l5, the piston stem 8, the bolt 31 and the central portion of the lever 36 to move outwardly to the position in which this piston assembly is shown in Fig. 1.

Immediately after the piston assembly starts to move from pneumatic lap position toward release position the end of the arm 41 of the lever 36 fulcrums on the fulcrum member ||4 and thereafter the continued movement of the piston stem 26 outwardly causes the arm 46 of the lever and thereby the plunger 48 to move in the direction of the piston l5 the plunger compressing the spring 54. The plunger in its movement i'lrst moves the pilot release valve 49 from its seat against the opposing seating pressure of the fluid in the chamber I8, and then, through the medium of the Valve stem 8| and stop nut 82, moves the main release valve 5|] out of engagement with its seat.

It will here be noted that when this pilot release valve 49 is unseated, uid under pressure iiows from the pressure chamber I9 to the piston chamber 69 by way of the bore 16 in the piston stem and the spaces between the collar 84 and the rear face of the piston 61 to the piston chamber 69. 'Ihe volume of the chamber 69 is smaller and the 110W of luid thereto is at a fairly rapid rate so that the pressure of fluid in the chamber I8 quickly equalizes into the chamber 69, the flow area of the passage 68 in the piston being so small that the flow of fluid therethrough from the chamber to the atmosphere will not materially interfere with such equalization.

Fluid under pressure admitted to the chamber E9 acts through the medium of the piston 81 to substantially unload the main release valve 58 so that substantially only the frictional resistance of the piston 61 and the iorce of the spring 54 need be overcome by the piston` assembly to unseat the valve.

With the main release valve 58 unseated, fluid under pressure flows from the brake cylinders l2 through the straight air pipe 1, the pressure chamber I9, past the unseated valve 5G, and to the exhaust port 1|, thus releasing the brakes.

The pneumatic portion of the relay valve device illustrated in Fig. 2 may be identical with that illustrated in Fig. 1,' the switch mechanism being somewhat different. The switch construction in Fig. 2 comprises a spring biased contact member 58| connected by the conductor |32 to the positive terminal of the battery |34, and normally biased by the bolt |66 into engagement with a contact member |52 that is connected to the release magnet valve wire |36, and that is adapted to be forced outl of engagement with the contact member |62 and into engagement with a contact member |63 that is connected to the application magnet valve wire |36.

In the form of the relay valve device 8 illustrated in Fig. 3 Vthe switch contact members are in a chamber |1| that is maintained at atmospheric pressure through an opening |12, and that is bounded at one side by a movable diaphragm |13 separating the chamber |1| from an operating chamber |18, that is connected by means of the control pipe 1 to be supplied with fluid under pressure in accordance with the movement of the brake valve device. The opposite side of the chamber i'll is bounded by a diaphragm |15 separating it from the self-lapping chamber |15 that is in communication with the pressure chamber i9 through a restricted passage |11 so that changes in pressure within the self-lapping chamber |16 take place gradually Within the chamber I8 as determined by the restricted passage |11. A follower plate |18 is positioned adjacent the movable diaphragm |13 and a follower plate |19 is positioned adjacent the movable diaphragm |15, these two follower plates being connected by a stem |8| to effect similar movement of the two diaphragms |13 and |15. The movement of this diaphragm assembly in one direction is limited by stops |82 that are adapted to engage the follower plate |19, and in the other direction by stops |83 that are adapted to engage the follower plate |18. An insulating member |84 is carried by the stem 18| and is provided with a switch contact member |85 that is movable with the stem |8|. A fixed switch contact member |86, mounted on a stop |81 in an insulating plate |88 in the wall of the relay structure 8, is connected by the wire |33 to the positive terminal of the battery |34. A xed switch Contact member |88 that is mounted on a stop |9| in the insulating plate |88, is connected to the application magnet valve wire |31, and a switch contact member |92 that is mounted on -a stop |93 is connected to the release magnet valve I wire |36. The switch member |85 is adapted to bridge the contact members |86 and |82 when the diaphragm assembly is in the illustrated position to effect the energization of the release magnet valve devices, and is adapted when the stem 18| is moved forwardly to bridge the switch Contact members |89 and |86, to effect the energization of the application magnet valve devices through the wire |31. In the forward movement of the diaphragms |13 and |15 from the illustrated position to the position in which the application magnet valve wire |31 is connected to the positive terminal of the battery |34, the switch contact member |85 passes through a position in which it engages neither of the contact members E92 or |89, in which position the magnets of the release magnet valve devices and also of the application magnet valve devices are all deenergized thus effecting lap position of the magnet valve devices.

The operation of the relay valve device illustrated in Fig. 3 is similar to that illustrated and fully described in respect to Fig. 1. The contact members of the electrical switch device may be so arranged that, upon movement of the stem I8I from lap position in either direction, the magnet valve device will be energized prior to the operation of the corresponding pneumatic valve portion of the relay controlled by the lever 36, so that the application and release of the brakes respectively are controlled primarily by the application magnet valve devices 9 and the release magnet valve devices I I.

The form of the relay device shown in Fig. 4 is substantially similar to that illustrated in Fig. 3 with the exception of the specific switch mechanism, in which a switch arm gill is provided mounted on a pivot pin 202 in the casing of the relay device structure, and provided at one end with an operating knob 2513 positioned in a recess in the stem I8I having bearing plates Zilli, the switch arm being provided at the other end with an insulating block 295 carrying a movable contact member 2GB. Stationary'contact members 2El'l, 2538, and 269 are mounted in a plate of insulating material 2H and connected respectively to the battery conductor |33, the release magnet valve wire ISS, and the application magnet valve wire I 3l. The contact member Zlii ris movable into and out of engagement with the contact members Zilli and 29% to effect the energization of the release magnet valve devices and of the application magnet valve devices, respectively, in accordance with the forward and backward movement of the stem IBI operatively connecting the follower plates i i5 and Il@ associated, respectively, with the diaphragme |13 and |15 in a manner to eifect an operation of the application magnet valve devices similar to that described with respect to the structure illustrated in Fig. l.

While certain embodiments of the invention have been illustrated and described it is apparent to one skilled in the art that many Vchanges in the details of apparatus and circuits may be made within the spirit of my invention, and I do not wish to be limited otherwise than by the scope of the appended claims.

Having now described my invention, what I claim as new and desire to secure by Letters Patent, is:

l. In a brake equipment for vehicles, a brake cylinder, means for controlling the application and release of the brakesv comprising brake valve device, a relay device responsive to the operation of said brake valve device and having an electrical portion and a pneumatic portion actuated by a common movable element, electrical means responsive to the operation oi said relay device for controlling the supply ci' fluid under pressure to, and the release of uid under pressure from, said brake cylinder, and valve means also responsive to the operation of said relay device for controlling the supply of fluid under pressure to and the release of fluid under pressure from said brake cylinder for controlling the application and release of the brakes upon failure or the operation of the electrical means.

2. In a brake equipment for vehicles, a brake cylinder, means for controlling the application and release of thek brakes comprising a brake valve device, a relay device having a control member responsive to the operation of said brake valve device, electrically operated means for controlling the supply of fluid under pressure to, and the release oi uid under pressure from, said brake cylinder, cont-act members operated by said relay controlling means for controlling the operation of said electrically operated means, and additional valve means controlled by said control member to correspondingly control the supply oi fluid under pressure to, and the release of fluid under pressure from, said brake cylinder independently of the operation of said electrically controlled valve means.

3. In a brake equipment for vehicles,l a brake cylinder, means for controlling the application and release of the brakes comprising a brake valve device, a relay device having a control member responsive to the operation of said brake valve device, electrically operated means controlled by said control member for controlling the supply of fluid under pressure to, and the release of uid under pressure from, said brake cylinder, and additional valve means controlled by said control member to correspondingly control the supply of iiuid under pressure to, and the release of fluid under pressure from, said brake cylinder independently of the operation of said electrically controlled valve means.

4. In a brake equipment for vehicles, a brake cylinder, means for controlling the application and release of the brakes comprising a brake valve device, a relay device having a control member responsive to the operation of the said brake valve device, electrically operated valve means for controlling the supply of fluid under pressure to, and the release of fluid under pressure from, said brake cylinder, and contact members operated by said relay control member for controlling the operation of said electrically operated valve means, and additional valve means controlled by said control member to correspondingly effect the supply of iiuid under pressure to, and the release of fluid under pressure from, said brake cylinder independently of the operation of said electrically controlled valve means, said contact members being arranged to effect the operation of said electrically controlled valve means prior to the operation of said additional valve meansupon the movement of said control member from lap position in either direction.

5. In a vehicle brake apparatus, the combination with a brake cylinder, a supply reservoir and a main reservoir pipe for charging said reservoir, of magnet valve devices for controlling the supply of fluid under pressure from said supply reservoir to said brake cylinder, a relay device for controlling said magnet valve devices and for also controlling the supply of iluid under pressure to and the release of fluid under pressure from said brake cylinder independently of said magnet valve devices, and a brake valve device for controlling the supply of fluid under pressure to said relay device.

6. In a train brake system, the combination i with a straight air brake equipment, of means for effecting an application of the brakes by straight air pipe operation and including a manually movable control device and a relay device controlled thereby, said relay device having a control chamber responsive to fluid under pressure supplied by said manually movable control device, and control :eans operative in accordance with the pressure in said control chamber for controlling tbe application of the brakes, means responsive to the operation of said relay control means for controlling the application of said brakes electrically` and means responsive to the operation of said relay control means for pneumatically controlling the application of said brakes independently of said electrically controlled means.

7. In a brake system for vehicles, in combination, a brake cylinder, a straight air` pipe for supplying fluid under pressure to sai-d brake cylinder, magnet valve devices for controlling the supply of iluid under pressure to and the release of fluid under pressure from said straight air pipe to control the application and release of the brakes, a control pipe, a relay device for controlling the operation of said magnet valve devices and having a control chamber subject to control pipe pressure and a self-lapping chamber subject to straight air pipe pressure and a control element subject to the dilerential pressures in said two chambers, switch contact members actuated by said control element for controlling the operation of said magnet valve devices and valve means also controlled by said control element for controlling the supply of fluid under pressure to and the release of iluid under pressure from said straight air pipe independently the operation of said magnet valve devices.

8. In a nuid pressure brake, in combination, a brake cylinder, a relay valve device having a movable abutment operated by fluid pressure for supplying uid under pressure to the brake cylinder, magnet valve devices also operative for supplying uid under pressure to the brake cylinder, and switch control members operated by said abutment for controlling the operation of said magnet valve devices to elect a parallel supply of fluid under pressure to the brake cylinder through said magnet Valve devices and through said relay valve device.

9. In a fluid pressure brake, in combination, a brake cylinder, a relay device having a control member operated by fluid pressure for supplying fluid under pressure to the brake cylinder, magnet valve devices Ialso operated for supplying fluid under pressure to the brake cylinders, and switch members actuated by said control member for controlling the operation of said magnet valve devices to eiect a parallel supply of luid under pressure to the brake cylinders through said magnet valve devices and through said relay valve device.

l0. In a fluid pressure brake, in combination, a brake cylinder, a relay device having a control member operated by fluid pressure for supplying fluid under pressure to the brake cylinder, magnet valve devices Ialso operative for supplying duid under pressure to the brake cylinder, and switch contact members actuated by said control member for controlling the operation of said magnet valve devices to eiect a parallel supply fluid under pressure to the brake cylinder through said magnet valve devices and through said relay valve device, the parts of said relay valve device being so arranged that the movement of said control member from release position to application position eifects pneumatic release, electric release, electric application, and pneumatic application in the order recited.

ll. In a fluid pressure brake, in combination, a brake cylinder, a relay device having a control element operated by iluid pressure corresponding to the desired degree of application of the brakes, a release valve and an application valve mechanically controlled by said control element for controlling the supply of fluid under pressure to and the release of fluid under pressure from sai-d brake cylinder, switch contact members controlled by said control element, a release magnet valve device and an application magnet valve device controlled by said switch contact members for controlling the supply of fluid under pressure to and the release of uid under pressure from said brake cylinder in parallel with the control of said fluid pressure and controlled by said first named release valve and application valve.

l2. In a fluid pressure brake, in combination, a brake cylinder, a relay device having a control element operated by fluid pressure corresponding to the desired degree of application or" the brakes, a release valve and an` application valve mechanically controlled by said control element for controlling the supply of iluid under pressure to and the release of fluid under pressure from said brake cylinder, switch contact members controlled by said control element, a release magnet valve device and an application magnet valve device controlled by said switch contact members for controlling the supply of fluid under pressure to and the release of uid under pressure from said brake cylinder in parallel with the control of said fluid pressure as controlled by first named release valve and application valve, said switch contact members being so arranged th-at in movement from lap position to application position the electrically controlled application valve operates in advance of the mechanically controlled application valve and in movement from lap to release position the electrically controlled release operates in advance of the mechanically controlled release valve.

13. In a brake equipment for vehicles, in combination, a brake cylinder, valve means for controlling the supply and release of iluid under pressure to and from the brake cylinder, a movable abutment operated by variations in iluid pressure for operating said valve means, a stem extending from one side of said abutment and operatively connected to said valve means, electrically controlled means for also controlling the supply and release of fluid under pressure to and from the brake cylinder, a second stem extending from the opposite side of said abutment, and contact members operable by said second stem for controlling the operation of said electrically controlled means.

la. In a fluid pressure brake, in combination, a brake cylinder, magnet valve devices for controlling the supply of fluid under pressure to and the release of fluid under pressure from said brake cylinder, a control device having a pair of space-d movable abutments connected by a common stern to eiect similar movements thereci, switch controlled members operated by said stem for controlling the operation of said magnet valve devices, means for controlling the supply of fluid under pressure to one side or" one of said -abutments at a pressure corresponding with the desired degree of application of the brakes, and means for supplying fluid under pressure to one side of the other abutment in accordance with brake cylinder pressure, sai-d stem and abutments being responsive to the differential pressures on said two abutments.

15. In a brake system for vehicles, in combination, a brake cylinder, a straight air pipe for supplying fluid under pressure to said brake cylinder, magnet valve devices for controlling the supply of fluid under pressure to and the release of fluid under pressure from said straight air pipe to control the application and release of the brakes, a control pipe, a relay device for controlling the operation of said magnet valve devices and having a control chamber subject to control pipe pressure and a self-lapping chamber subject to straight air pipe pressure and a control element subject to the diierential pressures in said two chambers, and switch contact members actuated by said control element for controlling the operation of said magnet valve devices.

16. In a brake system for vehicles, in combination, a brake cylinder, a straight air pipe for supplying fluid under pressure to said brake cylinder, magnet valve devices for controlling the supply of fluid under pressure to and the release of fluid under pressure from said straight air pipe to control the application and release of the brakes, a control pipe, a relay device for controlling the operation of said magnet valve devices and having a casing and two movable abutments therein dividing said casing into three chambers, a middle chamber, a control chamber at one end of the casing subject to control pipe pressure, a selflapping chamber at the other end of the casing subject to straight air pipe pressure, said movable abutment being connected by a stem to effect similar movements thereof and being subject to the differential pressure in said control chamber and said self-lapping chamber, and switch control members in the middle chamber actuated by said stem in accordance with the movement of said abutment for controlling the operation of said magnet valve devices.

17. In a fluid pressure brake, in combination, a brake cylinder, magnet valve devices for controlling the supply of fluid under pressure to and the release of fluid 'under pressure from said brake cylinder, a control device having a casing and two movable abutments therein dividing said casing into three chambers, a middle chamber open to the atmosphere, a control chamber on one side of the middle chamber subject to pressure for determining the degree of application of the brakes, a chamber on the other side of the middle chamber subject to brake cylinder pressure, said movable abutments being connected by a stem to effect similar movements thereof and being subject to the differential pressures in said two pressure chambers, and switch control means in the middle member actuated by said stern in accordance with the movements of said abutment for controlling the operation of said magnet valve devices.

18. In a fluid pressure brake equipment, in combination, means for operating the brakes, a control device therefor having a pair of spaced movable abutments connected by a common stem to effect corresponding movements thereof, switch control members operated by said stem for controlling the operation of said brake operating means, means for controlling the supply of fluid under pressure to one side of one of said abutments at a pressure corresponding to the kdesired degree of application of the brakes, and means for supplying fluid under pressure to one side of the other abutment in accordance with the actual degree of application of the brakes, said stem and abutments being responsive to the differential pressures on said two abutments.

19. In a fluid pressure brake equipment, in combination, brake operating means, a control device therefore having a casing and two movable abutments therein dividing said casing into three chambers, a middle chamber, a control chamber at one end of the casing subject to a pressure that varies in accordance with the desired degree of application of the brakes, a selflapping chamber at the other end of the casing subject to pressure that corresponds to the actual degree of application of the brakes, said movable abutments being connected by a stem to effect corresponding movements thereof and being subject to the differential pressures in said control chamber and said self-lapping chamber, and switch control members in the middle chamber actuated by said stem in accordance with the movement of said abutments for controlling the operation of said brake operating means.

20. In a fluid pressure brake system, in combination, a rst movable abutment subject to fluid under pressure supplied to a first chamber to a degree according to a desired degree of application of the brakes, a second movable abutment subject to fluid under pressure supplied to a second chamber according to the actual degree of application of the brakes, means interconnecting said two abutments and shifted according to the differential of pressure between said two chambers, and switch means operated by said interconnecting means for controlling the degree of application of the brakes.

21. In a fluid pressure brake system, in combination, a rst movable abutment subject to fluid under pressure supplied to a rst chamber to a degree according to a desired degree of application of the brakes, a second movable abutment subject to fluid under pressure supplied to a second chamber according to the actual degree of application of the brakes, means located between said abutments and shifted by said abutments according to the differential force of pressures acting on said abutments in said two chambers, and switch means operated by said last means for controlling the degree of application of the brakes.

22. In a fluid pressure brake system, in combination, a first movable abutment subject to fluid under pressure supplied to a first chamber to a degree according to a desired degree of application of the brakes, a second movable abutment subject to fluid under pressure supplied to a second chamber according to the actual degree of application of the brakes, means located between said abutments and shifted by said abutments according to the differential force of pressures acting on 'said abutments in said two chambers, circuit-controlling means conditioned according to the position assumed by said last means, and means controlled by the circuit-controlling means for controlling the degree of application of the brakes.

DONALD L. MCNEAL.

CERTIFICATE OF CORRECTION.

Patent Ho.. 12,068,345. January 19, 1937.

DONALD L. MCNEAL.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 9, first column, line 39, claim 1'7, for the'word "member" read chamber; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office,

'Signed and sealed this 6th day of April, A. D. 1937.

Henry Van Arsdale (Seal) Acting Commissioner of Patents. 

